The Everpure AIR FILTER RO is a high-performance replacement air filter designed specifically for reverse osmosis atmospheric storage tanks. Featuring a 0.2 micron hydrophobic filtration capability, this air filter effectively removes contaminants and ensures clean, purified air enters the storage tank. Its precise engineering guarantees compatibility with models 300-40005, making it an essential component for maintaining optimal performance in your reverse osmosis system. Enhance the longevity and efficiency of your water purification setup with this reliable air filter.